[PATCH v2 06/12] util: hash: Add delete-safe hash iterator

[Daniel Henrique Barboza]

On 11/4/20 2:05 PM, Peter Krempa wrote:
> 'virHashForEach' historically allowed deletion of the current element as
> 'virHashRemoveSet' didn't exits. To prevent us from having to deepy

s/exits/exist

Not sure if you meant 'deeply' instead of deepy (apparently deepy is a
slang for deep, according to google). Either way is fine AFAIC.


Reviewed-by: Daniel Henrique Barboza <danielhb413 at gmail.com>

> analyse all iterators add virHashForEachSafe which first gets a list of
> elements and iterates them outside of the hash table.
> 
> This will allow replace the internals of the hash table with other
> implementation which don't allow such operation.
> 
> Signed-off-by: Peter Krempa <pkrempa at redhat.com>
> ---
>   src/libvirt_private.syms |  1 +
>   src/util/virhash.c       | 26 +++++++++++++++++++++++---
>   src/util/virhash.h       |  1 +
>   3 files changed, 25 insertions(+), 3 deletions(-)
> 
> diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
> index 1793b81ad9..f7b0d11ca2 100644
> --- a/src/libvirt_private.syms
> +++ b/src/libvirt_private.syms
> @@ -2203,6 +2203,7 @@ virHashAtomicSteal;
>   virHashAtomicUpdate;
>   virHashEqual;
>   virHashForEach;
> +virHashForEachSafe;
>   virHashForEachSorted;
>   virHashFree;
>   virHashGetItems;
> diff --git a/src/util/virhash.c b/src/util/virhash.c
> index f205291de9..e54052985f 100644
> --- a/src/util/virhash.c
> +++ b/src/util/virhash.c
> @@ -481,7 +481,7 @@ virHashRemoveEntry(virHashTablePtr table, const char *name)
> 
> 
>   /**
> - * virHashForEach, virHashForEachSorted
> + * virHashForEach, virHashForEachSorted, virHashForEachSafe
>    * @table: the hash table to process
>    * @iter: callback to process each element
>    * @opaque: opaque data to pass to the iterator
> @@ -490,14 +490,14 @@ virHashRemoveEntry(virHashTablePtr table, const char *name)
>    *
>    * The elements are iterated in arbitrary order.
>    *
> - * virHashForEach allows the callback to remove the current
> + * virHashForEach, virHashForEachSafe allow the callback to remove the current
>    * element using virHashRemoveEntry but calling other virHash* functions is
>    * prohibited. Note that removing the entry invalidates @key and @payload in
>    * the callback.
>    *
>    * virHashForEachSorted iterates the elements in order by sorted key.
>    *
> - * virHashForEachSorted is more computationally
> + * virHashForEachSorted and virHashForEachSafe are more computationally
>    * expensive than virHashForEach.
>    *
>    * If @iter fails and returns a negative value, the evaluation is stopped and -1
> @@ -531,6 +531,26 @@ virHashForEach(virHashTablePtr table, virHashIterator iter, void *opaque)
>   }
> 
> 
> +int
> +virHashForEachSafe(virHashTablePtr table,
> +                   virHashIterator iter,
> +                   void *opaque)
> +{
> +    g_autofree virHashKeyValuePairPtr items = virHashGetItems(table, NULL, false);
> +    size_t i;
> +
> +    if (!items)
> +        return -1;
> +
> +    for (i = 0; items[i].key; i++) {
> +        if (iter((void *)items[i].value, items[i].key, opaque) < 0)
> +            return -1;
> +    }
> +
> +    return 0;
> +}
> +
> +
>   int
>   virHashForEachSorted(virHashTablePtr table,
>                        virHashIterator iter,
> diff --git a/src/util/virhash.h b/src/util/virhash.h
> index 1a59e9799d..b00ab0447e 100644
> --- a/src/util/virhash.h
> +++ b/src/util/virhash.h
> @@ -136,6 +136,7 @@ bool virHashEqual(const virHashTable *table1,
>    * Iterators
>    */
>   int virHashForEach(virHashTablePtr table, virHashIterator iter, void *opaque);
> +int virHashForEachSafe(virHashTablePtr table, virHashIterator iter, void *opaque);
>   int virHashForEachSorted(virHashTablePtr table, virHashIterator iter, void *opaque);
>   ssize_t virHashRemoveSet(virHashTablePtr table, virHashSearcher iter, const void *opaque);
>   void *virHashSearch(const virHashTable *table, virHashSearcher iter,
>